This invention relates generally to novel herbicidal compounds and methods for their use in controlling unwanted plant species in agriculture. In particular, it pertains to herbicidal heterocyclyl-spirobicyclic catechols , and more particularly it pertains to heterocyclyl-spirobicyclic catechols where the heterocyclyl portion is a 1-substituted-6-trifluoromethyl-2,4(1H,3H)-pyrimidinedion-3-yl, a 3,4,5,6-tetrahydrophthalimid-1-yl, a 2-5,6,7,8-tetrahydro-9-oxo-1H,3H-1,3,4!thiadiazolo3,4-a!pyridazineiminy l!, or a 1,6,8-triazabicyclo4.3.0!-nonane-7,9-dion-8-yl moiety.
There is a continuing demand for new herbicides. Herbicides are useful for controlling unwanted vegetation which may otherwise cause significant damage to crops such as wheat, corn, soybeans and cotton, to name a few. For crop protection, so-called "selective" herbicides are desired which can control the weeds without damaging the crop. Such crops are said to exhibit tolerance to the herbicide. In certain other situations, it is desirable to use herbicides that provide complete vegetation control such as in areas around railroad tracks and other structures. While many commercial products are available that provide selective or complete vegetation control, the demand exists for new, safe herbicides that are more effective and less costly.
U.S. Pat. No. 5,346,881 (FMC Corp.) describes herbicidally active compounds of the following formula: ##STR2## in which M is fluoroalkyl(C.sub.1-6); R is hydrogen, alkyl(C.sub.1-6), 2-alkynyl(C.sub.3-6), 2-alkenyl(C.sub.3-6), or cyanoalkyl(C.sub.1-6); R.sup.1 is hydrogen or alkyl(C.sub.1-6); R.sup.2 is hydrogen or alkyl(C.sub.1-6); X is hydrogen, fluorine, chlorine, bromine, cyano, alkyl(C.sub.1-6), or fluoroalkyl(C.sub.1-6); Y is hydrogen, fluorine, chlorine, or bromine, and n is 0or1.
U.S. Pat. No. 5,441,925 (FMC Corp.) describes herbicidally active compounds of formula I above in which M is fluoroalkyl(C.sub.1-6); R is amino; R.sup.1 is hydrogen or alkyl(C.sub.1-6); R.sup.2 is hydrogen or alkyl(C.sub.1-6); X is hydrogen, fluorine, chlorine, bromine, cyano, alkyl(C.sub.1-6), or fluoroalkyl(C.sub.1-6); Y is hydrogen, fluorine, chlorine, or bromine, and n is 0 or 1.